The increasing popularity of geographic information systems for natural resources management, terrain analysis and intelligence analysis has resulted in the production of videodisks for representing topographical maps, hydrographic charts and the like.
Maps and charts on videodisks are now been used as an alternative for paper maps. This technology consists of a videodisk player, a video monitor and, optionally, a graphic overlay board which are coupled to a computer, allowing users to consult, index and manage a bank of natural resources, terrain or similar information.
The videodisk is a support for geographic information systems which answers to a precise need: the consultation and editing of modifiable geographically referenced information on a stable geographic background. Several software packages have been developed (for example, FULCRUM (trademark) by Interactive Television Company (ITC) or VIDEOMAP by U.S.A. Defence Mapping Agency (DMA)) in association with cartographic videodisks to carry out various consultation functions:
viewing of a chart starting from the name of a town or of a continent; PA1 panoramic movement of the images; PA1 display of geographical coordinates; PA1 measurement of distance and travel; PA1 overlay of data, images and text; PA1 analysis of terrain and shapes; PA1 impression of parts of map or charts. PA1 a module for digitizing maps or charts; PA1 a module for processing the digitized data obtained; PA1 a module for video recording the processed data on an analog videotape; and PA1 a module for mastering a videodisk from the analog videotape.
The ITC process consists in capturing frames by means of a computer controlled 35 mm camera which is displaced step-by-step vertically in front of a horizontally moveable panel on which are mounted selected maps and/or charts. The captured photos are then put on a videodisk. The valid areas of each chart are cut and then adjacently pasted in a mosaic arrangement on the panel. Further, the camera is rotated so that the vertical central frame axis of the frame coincides with one of the geodesic meridian; thus the geodesic north is at the top of the frame. Simultaneously, the index and library files, which are necessary for the intelligent management of the images, are created.
This system, therefore, is entirely analog and mostly mechanical in concept. Thus, its use provides a considerable number of degradations and, also, a lack of flexibility. Finally, the numerous manual operations needed result in high costs.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.